No one is censoring anyone. They are free to post whatever toxic shit they want. But we, as an instance, have elected NOT to listen. Censorship would be banning their instance from existing, which IIRC is impossible with federated instances. No, this is just de-platforming. We are turning off the loudspeaker connected to their instance. We don't have to give them a platform. There is no reason to do so. So we defederate.

EDIT: Let me dumb it down further. "We are removing the link to Stormfront from our home page due to their stances." Would you call that censorship? Is it censorship that I would unfriend someone because they are spewing hateful garbage? Of course not. If you really want to read that hate, there are plenty of ways to find it. We just aren't going to help you find it anymore.